Precambrian glaciations and associated biospheric events

Precambrian glaciations are established to have occured during several brief periods in the Late Archean, Early Proterozoic, Late Riphean, and Vendian. These extreme climatic events of the Late Archean and post-Archean Earth history were accompanied by significant changes in the biosphere and biota. The terminal stages of Precambrian glaciations were marked by intense development of some existing groups, and the appearance of new groups of organisms. This may be explained by associated radical transformations of environments in all the biosphere subsystems, which resulted in substantial ecosystem and related biotic crises. The crises released former and yielded new ecological niches, on the one hand, and provoked enhanced mutations in organisms and rapid appearance of new forms, on the other. The most viable new forms as well as some of taxa that survived the crisis colonized released and newly formed niches to become more diverse and dominant groups. Thus, activation of abiotic and subsequent biotic factors during and after glaciations stimulated the renewal of the biota and acceleration of the evolutionary process.